Problem assigning action in BGE
I had met this problem.   And googled about this matter, but nothing helpful.
Eventually and suddenly when I applied the "subdivision surface" modifier to the rigid bodies (Remember: not the "armatures") surprisingly it done.
So to fix this first keep in mind to be sure to apply any Modifiers relate to the rigid bodies then look after other specifics in the (game logic bricks) if needed some works.
I added this information to my mind and hope to help others.. Thank you.